Method of and apparatus for preparing adhesive-covered cord



June 2, 1964 McGRATH ETAL 3,135,620

METHOD OF AND APPARATUS FOR PREPARING ADHESIVE-COVERED CORD Filed Dec.2'7, 1960 COOLING APPARATUS NVENTORS ATTORNEYv United States Patent3,135,620 METHOD OF AND APPARATUS FOR PREPARING ADHESIVE-COVERED CORDJohn J. McGrath, Arcadia, and Nathan M. Weiss, San Fernando, Calif.,assignors to Southland Cord and Machine Manufacturing Company, LosAngeles, Calif., a corporation of California Filed Dec. 27, 1960, Ser.No. 78,562

10 Claims. (Cl. 117-7) This invention relates to the preparation of cordmaterial of the twisted or braided type used for welting or boxing ofcushions or other forms of upholstery.

In the preparation of boxing for cushions and furni ture, it is wellknown that a cord is first attached to one or more of the edge portionsof the boxing after which it is sewed to the front and back surfaces ofthe cushion or other portions of the upholstered furniture. In the past,it was common practice to stitch or sew a cord at one edge of a boxingstrip, the strip being subsequently sewed to other portions of thecushion or piece of furniture. In many instances, two cords were used,one at each edge of the strip, the strip being sewn around the edges ofthe cushion or around the back and/or front of a piece of furniture.

The present invention relates to a method of preparing the cord so thatit may be adhesively attached to the edge portions of a strip of fabric,either cloth or plastic, and which will remain attached until the stripis sewed in its final position or separated by hand for splicing. Theinvention thus provides an adhesivecovered cord which can resisttemperatures up to approximately 200 degrees F. to withstand storage andshipping but which willbecome tacky or workable at approximately 250degrees F., a temperature which will not harm cloth or plastic. Theworking range of the adhesive is between 250 and 400 degrees F. In thisrange, the material may be heated in several manners, such as by contact.with electrically heated shoes or by hot air. The adhesive is also onewhich will not bleed through the material and whose adhesiveness canonly be destroyed by extremely high heat or solvent. It is athermoplastic which is flexible, slick, non-tacky, and dry at normaltemperatures, and iscomrnerically available.

Although this adhesive has these desirable characteristics, it may beapplied to the cord ina special manner. That is, a limitedamount must beapplied to prevent brittleness of the cord, since the cord must beflexible to make bends around corners of upholstery. It also must beapplied in sufiicient amounts and in the proper manner to insure theattachment-of the fabric to the cord. Furthermore, it is desirable thatthe ends of the fabric be easily removable from'the cord by hand topermit splices to be made between the ends of the strips of fabricmaterials.

The present invention is directed to a mechanism for applying adhesiveto cord so that it may be eventually satisfactorily .attached to fabricor plastic.

The principal object of'the invention, therefore, is to facilitate theapplication of an adhesive to a boxing cord.

Another object of the invention is to provide an improved method of andmeans for applying a thermoplastic adhesive to a cord to be eventuallyattached to a fabric.

A further object of the invention is to provide an improved method ofand apparatus for producing an adhesive-covered cord which will notadhere to contacting portions thereof but may be readily processed toadhere to fabrics and plastics.

A better understanding of this invention may be had from the followingdetailed description when read in connection with the accompanyingdrawings, in which:

FIG. 1 is a diagrammatic elevational view of a mechanism embodying theinvention;

' FIG. 2 is a cross-sectional view taken along the line 2-2 of FIG. 1;

FIG. 3 is a cross-sectional view taken along the line 3-3 of FIG. 2;

FIG. 4 is a perspective view of a portion of cord produced with theinvention; and

FIG. 5 is a perspective view showing the cord attached to a strip offabric.

Referring, now, to the drawings in which the same numerals refer to likeelements, a tank 5 contains a thermoplastic adhesive 6, such asmentioned above, in which are two commercial electrical heating units 7and 8. These heating units may be controlled by commercial thermostats.

From a supply reel 10, a twisted or braided cellulose or similar type ofboxing cord 11 is guided by a guide 9 and rollers 12 into a tube 19, thecord exiting from the tube into a cooling unit 14 from which it is fedover pulleys 15 and 16 to a takeup reel17 driven by a motor 18 whichpulls the cord through the tank 5 and unit 14. As shown in FIGS. 2 and3, the tube 19 has a wall 13 within which are quadrant sections 25 withend sections 26 and 27. Passing through the quadrant and end-sections isa lower centrally positioned longitudinal bore 20 of one diameter and anupper centrally positioned longitudinal bore 21 of a slightly largerdiameter connecting with the bore.'20. Four equally-spaced slots 22having tapered ends 23 permit the thermoplastic 6 to'reach the cord 11passing through the bore 20 and the lower end of bore 21. To furtherdescribe this unit, the insert in tube 19 is made up of bored endsections 26 and 27 which are integral with the intermediate be rotatedtovary the openings between slots therein and the slots 22 betweenquadrants 25.

- As mentioned above, a predetermined excessive amount of adhesivecannot be applied to the cord, as it destroys its" flexibility, but asufiicient amount must be applied to insure the desired bond between thecord and the material with'which it is used, the bond to be maintaineduntil the-boxing is sewn to other fabric with which it is used. Sincethe cord used in upholstery boxing is not'of constant or uniformdiameter throughout, the

application 'of -the adhesive must befapplied in a man ner to makecertain of a proper bond without rigidity. The adhesive mentioned aboveis one which will bond to a fabric or plastic in 'a manner similar tothe attachment of a moist warm element to cold metal, and is one whichwill not deposit on the guides through which the cord is directed duringthe attachment of the cord to the fabric. The proper amount of adhesiveand the special manner in which it is deposited on the cord isaccomplished by the apparatus above described.

As shown in FIG. 4, the cord 11 is of a spiral configurationandwhenpulled through the bore 20, the internal'diameter of which is veryslightly greater than the diameter of the cord 11, will twist by contactwith the wall of the bore. Thus, the adhesive passing through the slots22 to the cord 11 in bore 20 is applied intermittently in spiral rows orlines on the low spots of the cord as shown at 28. It has been found,however,

.that applying the adhesive only at the low spots on the Patented June2, 1964 disclosed and claimed in our copending application, Serial No.88,923, filed Feb. 13, 1961.

Thus, to provide smear points such as shown at 29 on the high points ofthe cord, the diameter of bore 21 is slightly larger to permit theliquid adhesive to flow to the high points. However, the speed of thecord through the bore 21, and the fact that the cord and adhesive are incontact only during the passage of the cord through the short lowerlength of the bore 21, only the desired amount of adhesive is applied assmears to the high points of the cord. By applying the adhesive inspirals, there will always be adhesive in contact with the boxingmaterial even when the cord is in contact along a narrow portion of thematerial, the smear spots insuring proper bonding when the edge portions30 and 31 of the material 32 are wrapped around cords 34 and 35 as shownin FIG. with the apparatus disclosed and claimed in our copendingapplication mentioned above. The cords are never completely covered bythe adhesive to avoid brittleness of the coated cords.

By passing the cord through the cooling apparatus 14 as it leaves thetube 19, the adhesive is immediately hardened and the cord may be woundon the reel 17 without fear of having the contacting turns adhere to oneanother during storage and shipping.

It is to be understood that other normally liquid types of adhesives maybe used, together with a drying step, before winding upon a storagereel.

We claim:

1. The method of applying an adhesive at predetermined points onatwisted cord, said adhesive being adapted to be subsequently heated forattachment to fabric, comprising obtaining an adhesive in liquid form,passing said cord through a tube having a bore of a diameterapproximately that of said cord, said cord being rotated as it passesthrough said bore due to the twist therein, said liquid flowing througha plurality of openings in the walls of said tube adjacent said cord toapply said liquid adhesive to said cord only at a plurality of pointslongitudinally and circumferentially thereof, passing said cord to aslightly larger diameter portion of said bore for a predetermined timeperiod determined by the speed of passage of said cord through saidlarger diameter portion for applying adhesive to said cord at otherpoints on said cord, and reducing said adhesive to a solid state.

2. The method in accordance with claim 1 in which said cord is rotatedby friction between the surface of said first-mentioned portion of saidbore andsaid cord to apply said adhesive to said cord in spiral rows.

3. The method in accordance with claim 1 in which said twisted cord isrotated during passage through said first-mentioned portion of said boreto apply said adhesive spirally to the low points of said cord while insaid firstmentioned portion of said bore, said adhesive being applied tothe high points on said cord in said larger portion of said bore,

4. Apparatus for applying a liquid adhesive to'a welting cord comprisingmeans for containing said adhesive in liquid form, a tube mounted in aside of said adhesivecontaining means and extending into said adhesive,said tube having longitudinal slots therein and enclosing'two axiallyinterconnected internal bores of different diameters, a portion of saidtube having the larger diameter bore extending above the surface of saidadhesive pas sages being provided between said slots and said bores toconduct said liquid adhesive from said adhesive containing means to saidbores, means for moving said cord through said bores, said cord movingfrom said smaller diameter bore to said larger diameter bore, and meansfor rendering said liquid adhesive solid after passage through saidbores.

5. Apparatus in accordance with claim 4 in which quadrant sections areenclosed in said tube and said passages include fourcircumferentially-positioned longitudinal slots between said sections inalignment with said slots in said tube through which said adhesive isconducted to said bores.

6. Apparatus for applying a normally solid adhesive to a cord of spiralconstruction comprising means for heating a solid adhesive to liquidform, means for containing said liquid adhesive, a tube attached to aside of said containing means and extending into said liquid, said tubehaving a portion thereof above the surface of said liquid and havinglongitudinally positioned slots therein connected with a pair of axiallypositioned bores of different diameters, quadrant section's enclosed bysaid tube, said sections having longitudinally positioned slots thereinin alignment with said slots in said tube and terminating at said bores,and means for moving said cord through said bores.

7. Apparatus in accordance with claim 6 in which each of said bores hasa different diameter, said cord having a diameter substantially that ofthe smaller bore 7 and being adapted to pass from the smaller diameterbore to the larger diameter bore, adhesive being applied through saidaligned slots to certain portions of the surface of said cord when insaid bore of smaller diameter and to other'portions of the surface ofsaid cord when in said bore of larger diameter.

8. Apparatus in accordance with claim 6 in which means are provided forcooling said adhesive applied to said cord to'a solid state.

9. Apparatus in accordance with claim 7 in which the friction betweensaid spirally constructed cord and the surface of said bore of smallerdiameter rotates said cord to apply said adhesive on said cord alongspiral lines as said cord moving means moves said cord through saidsmaller diameter bore, cooling means for said adhesive being provided.

10. Apparatus for applying a liquid adhesive to a welting cordcomprising means for containing said adhesive in liquid form, a tube insaid liquid adhesive in said containing means and having one endattached to a wall of said containing means and the other end above thethe surface of said adhesive, spaced quadrant sections in said tube toform a bore therein, said quadrant sections having end portions withbores therein of different diameters, a section of the larger diameterportion being above the surface of said adhesive, said tube havinglongitudinal slots therein aligned with the spaces between said quadrantsections to permit passage of said liquid adhesive to said bores, andmeans for moving said cord through said bores.

References Cited in the file of this patent UNITED STATES PATENTS874,287 Bayne et a1. Dec. 17, 1907 1,811,505 Kennedy June 23, 19312,146,314 Radford Feb. 7, 1939 2,255,436 Olson Sept. 9, 1941 3,042,570Bradt July 3, 1962

1. THE METHOD OF APPLYING AN ADHESIVE AT PREDETERMINED POINTS ON ATWISTED CORD, SAID ADHESIVE BEING ADAPTED TO BE SUBSEQUENTLY HEATED FORATTACHMENT TO FABRIC, COMPRISING OBTAINING AN ADHESIVE IN LIQUID FORM,PASSING SAID CORD THROUGH A TUBE HAVING A BORE OF A DIAMETERAPPROXIMATELY THAT OF SAID CORD, SAID CORD BEING ROTATED AS IT PASSESTHROUGH SAID BORE DUE TO THE TWIST THEREIN, SAID LIQUID FLOWING THROUGHA PLURALITY OF OPENINGS IN THE WALLS OF SAID TUBE ADJACENT SAID CORD TOAPPLY SAID LIQUID ADHESIVE TO SAID CORD ONLY AT A PLURALITY OF POINTSLONGITUDINALLY AND CIRCUMFERENTIALLY THEREOF, PASSING SAID CORD TO ASLIGHTLY LARGER DIAMETER PORTION OF SAID BORE FOR A PREDETERMINED TIMEPERIOD DETERMINED BY THE SPEED OF PASSAGE OF SAID CORE THROUGH SAIDLARGER DIAMETER PORTION FOR APPLYING ADHESIVE TO SAID CORD AT OTHERPOINTS ON SAID CORD, AND REDUCING SAID ADHESIVE TO A SOLID STATE.